We're told that exercise is supposed to make you thinner, sexier, more
energetic and (most magical of all) happier. Don't be so sure...

One of the few modern articles of faith is our belief in exercise. Even if you don’t do it, you know what its powers are. Exercise makes you thinner, sexier, more energetic and (most magical of all) happier. We are constantly urged to do more of it – especially our children, who will otherwise spend their whole lives lying on the sofa sending texts, being slowly engulfed by their adipose tissue until only a giant puddle of fat and two twitching thumbs remain.

Quick – send your young out to the playing fields! The NHS Live Well website advises that children aged five to 18 should do at least an hour a day of mixed-intensity aerobic exercise, as well as muscle-strengthening activities such as sit-ups, push-ups and “resistance exercises with exercise bands, weight machines or hand-held weights”.

Now, I don’t doubt that a bit of running around is good for children. I dutifully drag mine to the playground most days, for an hour of moaning and shivering and inching down the wet slide in their welly boots. If nothing else, it makes us all doubly happy to get home. But an actual exercise regime? Isn’t that the price you pay for being a grown-up? Pumping weights seems to me a poor use of the precious currency of childhood: time that could be spent battling superheroes, drawing on the carpet, trimming the cat’s whiskers, drooling contentedly in front of the telly, or – best by far – reading.

I find it just as weird when friends take their teenage children to the gym. Don’t they have malls to roam, boys to sext, rules to break? Something – anything – more joyful than running on the spot in pursuit of toned thighs? When I was little, in the Seventies, no British person of any age knowingly took exercise. They might have done it unwittingly – while going for a nice walk, say – but the idea of exercise as a virtuous activity in its own right had yet to cross the Atlantic.

The first time I ever saw someone jogging, I was driving through Richmond Park with my family. Dad pointed out of the window and said: “What’s that man running away from?” Mum said: “Look at his tiny shorts!” We concluded that he must be either crazy or on the run from the police, so we didn’t stop to help.

It was another decade or so before madmen in tiny shorts became a common sight on British streets. In the meantime, I had the benefit of a thoroughly indolent childhood. Apart from unavoidable movements (such as walking to school) and occasional fun ones (sledging down the stairs in a sleeping bag), I hardly used my body at all. Mostly, I was either lying down to read, or sitting up to eat.

This torpid upbringing doesn’t seem to have done much physical damage (says she, keeling over with a massive coronary). And I still believe that the habit of reading was – and is – at least as good for my mental health as any exercise regime.

The good news is, science may be coming round to this view. Indeed, a report published by Swiss researchers this week claims that too much exercise can make teenagers miserable. Led by the distinguished paediatrician Joan-Carles Suris, and based on studies of 1,200 adolescents, it found that a moderate amount of physical activity did make them happier. But those who were exercising for two or more hours a day reported lower levels of emotional wellbeing.

Dr Suris argues that doctors may be putting too much faith in the magic of exercise. “As paediatricians, we ask children if they practise sport. If they say, 'Yes, three hours a day,’ we think, 'Great – this guy has no problems.’ Maybe, though, we should ask, 'Are you happy? Would you prefer to read a book?’ ”